This invention relates generally to a device for coupling optical fibers and, more particularly, to an apparatus that provides structural rigidity in panel-mounted applications and enables high-density optical fiber interconnections.
Optical fiber systems require that optical signals be routed to one destination and periodically re-routed to another destination. Such routing takes place at various locations along a transmission path. For example, Lucent Technologies has designed an optical switch that uses 256 or more movable mirrors to selectively route the paths of optical signals among a number of optical fibers that are coupled to the switch. The switch is generally administered through a connection panel that terminates a large number of optical fibers, each of which terminates in an optical plug. Coupling apparatus is installed in the panel for enabling interconnection between individual pairs of optical plugs.
One example of optical coupling apparatus is shown in U.S. Pat. No. 5,274,729 that issued on Dec. 28, 1993 in the names of King et al. The King et al. reference discloses a number of xe2x80x9cblocksxe2x80x9d that are adapted for mounting to a panel through a plurality of openings provided therein. The King et al. system further includes a number of xe2x80x9cbuildouts,xe2x80x9d that are adapted to be removably attached to the blocks that are mounted on the connection panel. Each connecting block includes a front aperture that forms a keyway, which is adapted to align and receive a cylindrical boss that holds an alignment sleeve. And while the King et al. system functions adequately, demand for an increasing number of optical fiber connections has prompted the design of smaller optical fiber plug connectors that occupy less space.
U.S. Pat. No. 5,481,634 issued on Jul. 8, 1997 and discloses a low-profile, optical fiber plug connector. Its design is advantageous because it has a smaller footprint than any of its predecessor connectors and therefore requires less panel space. But while the development of the LC connector has shown that an optical plug connector can be successfully reduced in size, such size reduction is wasted unless the panel-mounted connecting hardware can accommodate an increased density of such reduced-size optical plugs.
An optical coupling apparatus that uses the LC plug connector is shown in U.S. Pat. No. 5,647,043, which discloses a jack receptacle that snaps into a connecting panel. The receptacle is fully assembled prior to panel mounting, which means that the type of optical plugs that can be used on the panel is fixed at the time of installation. And in order to accommodate the installation and removal of optical plugs, adjacent rows of optical ports are inverted with respect to each other in order to enable a user to operate the cantilever latches it may not be convenient to construct an array of jack receptacles having more than two rows since the optical plugs are inverted for accessibility to their latches. Such inversion may even lead to connection error in a situation where duplex optical connectors are used because the left-to-right orientation of the transmitting and receiving fibers is reversed between rows.
Accordingly, it is desirable to provide connecting hardware for use in a connection panel that enables high-density optical interconnections between optical plug connectors. Additionally, it is desirable that the connecting hardware accommodate duplex optical connectors, and that the duplex optical connectors accommodate different types of optical plugs. Finally, it is desirable that the connecting hardware have a uniform structure throughout so that left-to-right reversals of transmitting and receiving fibers are avoided when duplex connectors are used.
A high-density optical connecting block is designed to mount in a generally flat panel and includes a number of interlocked horizontal and vertical ribs that form an array of cells. The array includes at least twelve cells that are arranged in two or more rows and two or more columns. The front side of each cell includes recesses that are shaped to receive and interlock with a duplex optical connector.
In a preferred embodiment of the invention, each cell has a back side that is shaped to receive and interlock with a pair of individual optical plugs. Preferably, the connecting block is molded as a unitary structure from a polymeric material and includes thirty-six cells, which are disposed in three rows and twelve columns. Also, preferably, the connecting block includes keying features on opposite sides thereof so that when they are mounted side-by-side in a panel, adjacent connecting blocks can only be installed in one orientation.
In the illustrative embodiment, the front side of the connecting block further includes a pair of openings for receiving guide members that are positioned on the top and bottom sides of the duplex optical connector, and each opening includes a retaining surface molded therein for interlocking with the guide members on the duplex connector. Moreover, the openings are shaped to allow the duplex connector to fit into a cell in only one orientation. Illustratively, the vertical and horizontal ribs have a front-to-back depth that is greater than 10 millimeters for imparting flexural rigidity to the panel.